Answer
(a) $-57cm$
(b) $1.1m$
Work Step by Step
(a) $M_{total}=-\frac{f_{objective}}{f_{eyepiece}}$
This can be rearranged as:
$f_{eyepiece}=-\frac{f_{objective}}{M_{total}}$
We plug in the known values to obtain:
$f_{eyepiece}=-\frac{1.7}{3.0}=-57cm$
(b) We can find the distance between the two lenses as
$L=f_{objetive}+f_{eyepiece}$
We plug in the known values to obtain:
$L=1.7-0.57=1.1m$
